求linux的ip地址

#include <stdio.h>#include <stdlib.h>#include <string.h>int main(){    system("ifconfig > ip_info");    FILE* fp = fopen("ip_info","r");    //求文件大小    int file_size;    fseek(fp,0,SEEK_END);    file_size = ftell(fp);    rewind(fp);    //申请空间    char* ip_info = malloc(file_size+1);//'\0'    memset(ip_info,0,file_size+1);//清零，制造结束符    fread(ip_info,1,file_size,fp);//文件读入文件ip    // 查找子字符串       char* p = strstr(ip_info,"inet addr:");    char ip[16];       //网络ip:四段点分式,四个字节存储,或者16个字符    if(NULL == p)    {        fprintf(stderr,"网络配置异常！\n");    }    else    {        p += strlen("inet addr:");           sscanf(p,"%s",ip);//串io        printf("inet addr:%s\n",ip);    }    free(ip_info);    fclose(fp);    system("rm -rf ip_info");       return 0;}